The present invention relates to a data reproduction apparatus and a data storage medium that can be preferably applied to, for example, those using a storage medium with digitalized moving picture stored therein.
A conventional data reproduction apparatus that reproduces data from a disk as a storage medium with digitalized moving picture stored therein is described as a variable-rate-sensitive data reproduction apparatus as shown in FIG. 12 in the applicant""s Japanese Patent Laid Open No.6-124,168 (publicized on May 6, 1994). This reproduction apparatus reproduces data stored on an optical disk 101 using a pickup 102. The pickup 102 irradiates the optical disk 101 with laser beams and uses light reflected from the optic disk 101 to reproduce the data stored therein. Signals reproduced by the pickup 102 are delivered to a demodulator 103. The demodulator 103 demodulates the reproduced signals output by the optic pickup 102 to output them to a sector detector 104.
The sector detector 104 detects an address stored in each sector from the delivered data to output it to a ring buffer control circuit 106. It also outputs the data to an ECC circuit 105 located after the sector detector while maintaining sector synchronization. The sector detector 104 outputs a sector number error signal to a track jump determination circuit 118 via the ring buffer control circuit 106 if the detector fails to detect addresses or if detected addresses are not continuous.
The ECC circuit 105 detects an error in data supplied by the sector detector 104, and uses redundant bits contained in the data to correct the error to output the corrected data to a ring buffer memory (FIFO) 107 for the ring jump. Furthermore, if the ECC circuit 105 fails to correct an error in data, it outputs an error generation signal to the track jump determination circuit 118.
The ring buffer control circuit 106 controls writes to and reads from the ring buffer memory 107, and monitors a code request signal requesting data output from a multiplexed data separation circuit 108.
The track jump determination circuit 118 monitors the output of the ring buffer control circuit 106 to output a track jump signal to a tracking servo circuit 117 as required to track-jump the reproduction position of the pickup 102 relative to the optical disk 101. The track jump determination circuit 118 also detects a sector number error signal from the sector detector 104 or an error generation signal from the ECC circuit 105 to output the track jump signal to the tracking servo circuit 117 to track-jump the reproduction position of the pickup 102.
The output of the ring buffer memory 107 is supplied to the multiplexed data separation circuit 108. A header separation circuit 109 in the multiplexed data separation circuit 108 separates pack headers and packet headers from data supplied from the ring buffer memory 107 to deliver them to a separator control 111, and supplies time-division-multiplexed data to the input terminal G of a switching circuit 110. The output terminals (switched terminals) H1, H2 of the switching circuit 110 are connected to the input terminals of a video code buffer 113 and an audio code buffer 115, respectively. The output of the video code buffer 115 is connected to the input of a video decoder 114, while the output of the audio code buffer 115 is connected to the input of an audio decoder 116.
In addition, code request signals generated by a video decoder 114 are input to the video code buffer 113, while code request signals generated by the video code buffer 113 are input to the multiplexed data separation circuit 108. Similarly, code request signals issued by an audio decoder 116 are input to the audio code buffer 115, while code request signals issued by the audio code buffer 115 are input to the multiplexed data separation circuit 108.
The operation of each component of this data reproduction apparatus is described next. The pickup 102 irradiates the optical disk 101 with laser beams, and uses light reflected from the optical disk to reproduce the data stored therein. Reproduced signals output by the pickup 102 are input to the demodulator 103 for demodulation. The data demodulated by the demodulator 103 is input to the ECC circuit 105 via the sector detector 104 to detect and correct an error.
A sector number error signal is output to the track jump determination circuit 118 if the sector detector 104 fails to detect sector numbers (the addresses assigned to the sectors of the optical disk 101) correctly. The ECC circuit 105 outputs an error generation signal to the track jump determination circuit 118 if an uncorrectable error is occurring in the data. Corrected data is delivered from the ECC circuit 105 to the ring buffer memory 107 for storage.
The ring buffer control circuit 106 reads the address of each sector from the output of the sector detector 104 to designate the write address (write point (WP)) on the ring buffer memory 107 corresponding to the address of the sector. The ring buffer control 106 also designates read addresses (reproduction points (RPs)) for the data written to the ring buffer memory 107 based on a code request signal from the multiplexed data separation circuit 108 located after the ring buffer control. It then reads data from the reproduction points (RP) to supply them to the multiplexed data separation circuit 108.
The head separation circuit 109 in the multiplexed data separation circuit 108 separates pack headers and packet headers from the data delivered by the ring buffer memory 107 to supply them to the separation circuit control circuit 111. The separation circuit control circuit 111 sequentially connects the input terminal G of the switching circuit 110 to the output terminal (switched terminal) H1 or H2 thereof according to the stream ID information in the packet headers delivered from the header separation circuit 109 to separate the time-division-multiplexed data correctly. It then supplies the data to the corresponding data buffer 113 or 115.
The video code buffer 113 issues a code request signal to the multiplexed data separation circuit 108 using the available section of its internal code buffer. The buffer 113 then stores received data. It also receives code request signals from the video decoder 114 to output data it contains. The video decoder 114 reproduces video signals from the supplied data to output them from the output terminal.
The audio code buffer 115 issues a code request signal to the multiplexed data separation circuit 108 using the available section of its internal code buffer. The buffer 115 then stores received data. It also receives code request signals from the audio decoder 116 and outputs data it contains. The audio decoder 116 reproduces audio signals from the supplied data to output them from the output terminal.
The video decoder 114 thus requests data from the video code buffer 113, while the video code buffer 113 requests data from the multiplexed data separation circuit 108. The multiplexed data separation circuit 108 in turn requests data from the ring buffer control circuit 106. In this case, data flows from the ring buffer memory 107 in the direction reverse to the request.
For example, reads from the ring buffer memory 107 decrease with the decreasing amount of data consumed by the video decoder 114 per unit time due to continuous data processing for simple screens. In this case, the amount of data stored in the ring buffer memory 107 may increase, resulting in overflow. The track jump determination circuit 118 thus uses write points (WPs) and reproduction points (RPs) to calculate the amount of data currently stored in the ring buffer memory 107 and, if the data exceeds a predetermined criteria, determines that the ring buffer memory may overflow to output a track jump instruction to the tracking servo circuit 117.
If the track jump determination circuit 118 detects a selector number error signal from the sector detector 104 or an error generation signal from the ECC circuit 105, it uses write addresses (WPs) and read addresses (RPs) to calculate the amount of data remaining in the ring buffer memory 107 and the amount of data required to ensure reads from the ring buffer memory 107 to the multiplexed data separation circuit 108 while the optical disk 101 is making a single rotation from the current track position (that is, while waiting for the optical disk 101 to make a single rotation).
If a large amount of data remains in the ring buffer memory 107, the track jump determination circuit 118 determines that the error can be recovered by forcing the pickup 102 to retry to reproduce data from the position where the error has occurred and outputs a track jump instruction to the tracking servo circuit 117 because an underflow does not occur even if data is read from the ring buffer memory 107 at the maximum transfer rate.
When the track jump instruction is output from the track jump determination circuit 118, for example, the tracking servo circuit 117 forces the pickup 102 to jump from position A to position B inner-circumferentially one track off from position A, as shown in FIG. 13. The ring buffer control circuit 106 inhibits new data from being written to the ring buffer memory 107 and the data stored in the ring buffer memory 107 is transferred to the multiplexed data separation circuit 108 as required until the optical disk makes another single rotation from position B to position A, that is, until the sector number obtained from the sector detector 104 becomes equal to that obtained before the track jump.
Even when the sector number obtained from the sector detector 104 becomes equal to that obtained before the track jump, writes to the ring buffer memory 107 are not restarted and another track jump is performed if the amount of data stored in the ring buffer memory 107 exceeds the predetermined criteria, that is, if the ring buffer memory 107 may overflow. The data reproduction apparatus can thus use the ring buffer memory 107 to address a variable rate and to carry out retries on errors.
The usefulness of this conventional data reproduction apparatus can be substantially improved by synchronously reproducing multiplexed data with video, audio, and superimposed dialogue data compressed at a variable rate in conformity with ISO11172 (MPEG1) or ISO13818 (MPEG2) while correcting synchronization errors and to perform a search, a halt, or a frame feed operation on errors.
In view of the above points, this invention proposes a data reproduction apparatus that synchronously reproduces multiplexed data with video, audio, and superimposed dialogue data compressed at a variable rate and performs various functions as well as a data storage medium associated with this device.
To achieve this object, this invention sets negative sector numbers to some sectors in a data storage medium that stores and reproduces data in sectors.
A data reproduction apparatus for reproducing data according to this invention reproduces data from a data storage medium with data stored in sectors using sector numbers as well as the negative sector numbers set to some sectors.
This invention stores, in predetermined positions on a data storage medium with multiplexed data comprising image data, audio data, superimposed dialogue data, and/or other data stored therein, multiplexing information indicating whether or not this data is multiplexed.
This invention also reads, from predetermined positions on a data storage medium with multiplexed data comprising image data, audio data, superimposed dialogue data, and/or other data stored therein, multiplexing information indicating whether or not this data is multiplexed.
This invention also stores positional information for access points used for data search and random access, in predetermined positions on a data storage medium with multiplexed data comprising image data, audio data, superimposed dialogue data, and/or other data stored therein.
This invention also reads positional information for access points used for data search and random access from predetermined positions on a data storage medium with multiplexed data comprising image data, audio data, superimposed dialogue data, and/or other data stored therein.
A data reproduction apparatus according to this invention having an error correction device, a ring buffer, a video code buffer, an audio code buffer, and/or a superimposed dialogue code buffer tests the operation of the memory contained in one or more of the above devices when activated or at an arbitrary point in time.
A data reproduction apparatus according to this invention using two types of error correction symbols associated with different interleaving directions to correct errors in reproduced data has an error correction device capable of varying the number of times that errors are corrected.
A data reproduction apparatus according to this invention which rereads data from the position where an error has occurred when the error is uncorrectable, automatically switches the number of times that data is reread, depending on operational conditions or the type of data to be reproduced.
A data reproduction apparatus according to this invention which can vary the number of times that errors are corrected and the number of times that data is reread automatically switches the number of times and the order that errors are corrected and that data is reread, depending on operational conditions or the type of data to be reproduced.
A data reproduction apparatus according to this invention comprising a buffer for reading at a variable rate or a buffer for rereading data when a data readout from a storage medium fails stores in a buffer memory information for the contents of data stored in the data storage medium.
The data reproduction apparatus according to this invention comprising a buffer for reading at a variable rate or a buffer for rereading data when data read from a storage medium fails stores in the buffer memory positional information for access points used for search and random access.
A data reproduction apparatus according to this invention for reproducing data from a data storage medium with image, audio, or superimposed dialogue data or other data stored therein automatically reproduces all or part of the image, audio, and/or superimposed dialogue data stored in the storage medium when the apparatus is activated, or when the storage medium is installed if the medium is removable.
In a data storage medium according to this invention having image, audio, or superimposed dialogue data or other data stored therein, reproduced data is written to specific positions when all or part of the stored image, audio, and/or superimposed dialogue data is automatically reproduced when the apparatus is activated, or when the storage medium is installed if the medium is removable.
A data reproduction apparatus for reproducing data from a data storage medium with image, audio, or superimposed dialogue data or other data stored therein automatically reproduces all or part of the image, audio, and/or superimposed dialogue data stored in the storage medium when the reproduction of part or all of the stored image, audio, and/or superimposed dialogue data is finished, suspended, or halted.
In the data storage medium according to this invention having image, audio, or superimposed dialogue data or other data stored therein, reproduced data is written to specific positions when all or part of the stored image, audio, and/or superimposed dialogue data is automatically reproduced when the reproduction of part or all of the stored image, audio, and/or superimposed dialogue data is finished, suspended, or halted.
A data reproduction apparatus according to this invention for reproducing multiplexed data comprising image, audio, and/or superimposed dialogue data has a multiplexing detection means for detecting whether or not the image, audio, and superimposed dialogue data is each multiplexed in the multiplexed data.
In a data reproduction apparatus according to this invention having a video code buffer, an audio code buffer, and/or a superimposed dialogue code buffer, a buffer memory has stored therein the video, audio, and/or superimposed dialogue data as well as information for data decoding start time inserted into the audio or the superimposed dialogue data.
This invention also has a reference clock for detecting an error in the synchronization of the reproduction time or the decoding start time of the video, audio, and superimposed dialogue data and measuring the magnitude of the error.
To start reproduction of multiplexed data with video and audio data, this invention skips the audio data instead of decoding it or clears all or part of a buffer for storing audio data to enable the audio data to have an earlier decoding start time than the video data so that the decoding of the video data can be started earlier than that of the audio data if comparison of the video decoding start time with the audio decoding time shows that the former is earlier than the latter.
This invention also starts reproduction of video, audio, or superimposed dialogue data in synchronization with a vertical synchronization signal.
A data reproduction apparatus according to this invention which can reproduce multiplexed data with video and audio data starts reproduction of the audio data in synchronization with the video data being reproduced and a reference clock in operation if the audio data is detected for the first time after reproduction of the video data has only been started.
A data reproduction apparatus according to this invention which can reproduce multiplexed data with video and superimposed dialogue data starts reproduction of the video data in synchronization with the audio data being reproduced and a reference clock in operation if the video data is detected for the first time after reproduction of the audio data has only been started.
A data reproduction apparatus according to this invention which can reproduce multiplexed data with video and superimposed dialogue data starts reproduction of the video data in synchronization with the superimposed dialogue data being reproduced and a reference clock in operation if the video data is detected for the first time after reproduction of the superimposed dialogue data has only been started.
A data reproduction apparatus according to this invention which can reproduce multiplexed data comprising audio and superimposed dialogue data starts reproduction of the audio data in synchronization with the superimposed dialogue data being reproduced and a reference clock in operation if the audio data is detected for the first time after reproduction of the superimposed dialogue data has only been started.
A data storage medium according to this invention for storing multiplexed data with video data in conformity with ISO11172 (MPEG1) or ISO13818 (MPEG2) or a plurality of data including such video data ensures that decoding start information is encoded for each picture.
A data reproduction apparatus according to this invention for reproducing video data in conformity with ISO11172 (MPEG1) or ISO13818 (MPEG2) having a means for detecting picture heads and the type of pictures carries out fast-forward reproduction by reproducing I- and P-pictures without reproducing B-pictures.
A data reproduction apparatus according to this invention for reproducing video and audio data comprising an error correction device for correcting errors in data read from a storage medium temporarily stops video output, reduces the brightness of a screen, outputs a blue or other color screen, stops audio output, or reduces the output level at the moment when the data in which an error has occurred is reproduced if the error cannot be corrected by the error correction device.
A data reproduction apparatus comprising an error correction device for correcting errors in data read from a storage medium and a mechanism for counting the number of times that an error that cannot be corrected by the error correction device skips data to be reproduced or aborts reproduction depending on the number or the frequency of errors that have occurred during a specified length of time.
A data reproduction apparatus according to this invention for reproducing video data in conformity with ISO11172 (MPEG1) or ISO13818 (MPEG2) having a means for detecting picture heads and the type of pictures and performing search operation by track jump repeats to carry out search operations in both forward and reverse directions when a P- or a B-picture is detected immediately after only I-pictures are selected and reproduced.
A data reproduction apparatus according to this invention for reproducing multiplexed data with video, audio, and/or superimposed dialogue data stops loading audio and/or superimposed dialogue data into a code buffer, periodically clears the code buffer, or instructs search for information for superimposed dialogue decoding start time, when searching for video data or feeding frames.
Data is reproduced according to sector numbers, and negative sector numbers set to some sectors are also reproduced. Multiplexed data with video, audio, and superimposed dialogue data compressed at a variable rate can be synchronously reproduced and various functions can be executed by storing, in the positions represented by these negative sector numbers, multiplexing information indicating whether or not the image, audio, and superimposed dialogue data is each multiplexed in the multiplexed data and positional information for access points used for data search and random access, and reproducing this information.